Refrigerator unit and/or a freezer unit as well as a method for the control thereof

ABSTRACT

The present invention relates to a refrigerator unit and/or freezer unit comprising a refrigerant circuit, which has a compressor, a condenser, at least one capillary tube as well as at least one evaporator, and a control device for the control of the refrigerant flow through the refrigerant circuit. The invention further relates to a method for the control of such a refrigerator unit and/or freezer unit, wherein at least one operating parameter and/or ambient parameter of the refrigerator unit and/or freezer unit is detected and the refrigerant flow is controlled by the refrigerant circuit in dependence on the detected operating parameter and/or ambient parameter. It is proposed in accordance with the invention to control the refrigerant flow in that the capillary tube is heated by means of a heating device and thereby causing the refrigerant flowing through the capillary tube to evaporate. The invention is based on the recognition that vapor produced in the capillary tube can considerably reduce and optionally completely prevent the flow of the refrigerant through the capillary tube. The greater the evaporation produced in the capillary tube, the lower the remaining refrigerant flow through the capillary tube.

The present invention relates to a refrigerator unit and/or freezer unit comprising a refrigerant circuit, which has a compressor, a condenser, at least one capillary tube as well as at least one evaporator, and a control device for the control of the refrigerant flow through the refrigerant circuit.

The invention further relates to a method for the control of such a refrigerator unit and/or freezer unit, wherein at least one operating parameter and/or ambient parameter of the refrigerator unit and/or freezer unit is detected and the refrigerant flow is controlled by the refrigerant circuit in dependence on the detected operating parameter and/or ambient parameter.

As a rule, valves such as monostable or bistable solenoid valves or also motor-driven valves are used for the control of the refrigerant flow through the refrigerant circuit of refrigerator and/or freezer units. DE 36 01 817 A1, for example, shows a regulator apparatus for the refrigerant inflow to the evaporator of such a refrigerant circuit, said regulator apparatus comprising an expansion valve actuable by an electrical actuating motor. DE 33 24 590 C2, in contrast, shows an electromagnetic on/off valve with whose aid the refrigerant flow can be selectively guided to a freezer compartment evaporator or to a refrigerator compartment evaporator of a refrigerator and/or freezer unit. The moving valve body is problematic, on the one hand, with such valves for the control of the refrigerant flow. This can result in functional disturbances or unwanted noises. The additional connection points, which are caused by the installation of the valves into the refrigerant circuit, are furthermore problematic with such valves. They are expensive, on the one hand, and moreover bring along the risk of a potential leak. In addition, relatively high component costs result due to the valves.

The present invention wants to provide a remedy here. It is its underlying object to provide an improved refrigerator and/or freezer unit as well as an improved method for the control of such a refrigerator and/or freezer unit which avoid the disadvantages of the prior art and further develop the latter in an advantageous manner. An improved control of the refrigerant flow with a reduced risk of leaking, which works without noise, should preferably be achieved with simple means.

This object is solved in accordance with the invention by a refrigerator unit and/or freezer unit in accordance with claim 1. The object is solved in a technical method aspect by a method in accordance with claim 16. Preferred aspects of the invention are the subject of the dependent claims.

It is therefore proposed in accordance with the invention to control the refrigerant flow in that the capillary tube is heated by means of a heating device and thereby causing the refrigerant flowing through the capillary tube to evaporate. The invention is based on the recognition that vapor produced in the capillary tube can considerably reduce and optionally completely prevent the flow of the refrigerant through the capillary tube. The greater the evaporation produced in the capillary tube, the lower the remaining refrigerant flow through the capillary tube.

In a further development of the invention, the control of the refrigerant flow can completely dispense with flow regulation valves and on/off valves. The control of the refrigerant flow can be effected solely by the heating of the capillary tube or of a plurality of capillary tubes and by the evaporation of the refrigerant therein. Additional connection points in the refrigerant circuit such as would be required for the installation of valves are thereby omitted. The risk of leaking can be reduced accordingly. In addition, the switching noises usually arising with valves are eliminated. The control of the refrigerant flow can be carried out completely free of noise. In addition, lower costs can be achieved in comparison with a valve solution since the heating device is much cheaper in comparison with the relatively expensive valves.

In an alternative further development of the invention, the control of the refrigerant flow can also take place by a combination of flow regulator valves and on/off valves, on the one hand, and of the heating of the capillary tube or of a plurality of capillary tubes, on the other hand. A greater variability of the control possibilities can thereby optionally be achieved. The previously described performance possibility with a complete omission of control valves, however, has clear advantages with respect to the costs, the risk of leaking and the forming of noise.

In accordance with an advantageous embodiment of the invention, the heating device is arranged at the end section of the respective capillary tube at the downstream side. If the capillary tube is heated directly in front of the injection position at its end, a particularly efficient control of the refrigerant flow can be achieved.

In an alternative embodiment of the invention, the heating device is arranged at the upstream end section of the respective capillary tube. Surprisingly, the refrigerant flow can already be controlled extremely precisely by heating the inlet section of the capillary tube.

The heating device itself can generally have different designs. In accordance with an advantageous embodiment of the invention, a resistance heating with relatively low power can be used which is seated in the respective capillary tube.

The heating output introduced into the capillary tube and/or the temperature of the capillary tube can preferably be changed in at least a plurality of steps, in particular in a stepless manner. A stepless control of the refrigerant flow through the refrigerant circuit can thereby optionally be achieved. If the capillary tube is only heated slightly above the point at which vapor formation occurs, a remaining refrigerant flow can still pass through the capillary tube. If, in contrast, the capillary tube is heated more and more strongly and if the vapor formation is accordingly increased more and more, less and less refrigerant can pass through the capillary tube.

In a further development of the invention, the heating device is made with stepless temperature control for this purpose and can be controlled accordingly by the control device which can have a temperature regulator or a temperature control module for this purpose. Alternatively or additionally, provision can also be made to change the length of the heated capillary tube section, for example by switching in further heating elements, and to thereby influence the vapor formation.

The heating output of the heating device can be controlled in dependence on different operating parameters of the refrigerator unit and/or freezer unit. An evaporator temperature, a refrigerator compartment temperature, a freezer compartment temperature and/or the ambient temperature of the refrigerator unit and/or freezer unit is preferably detected by means of at least one temperature sensor. The control device controls the heating device in dependence on the temperature detected in order to control the refrigerant flow accordingly. Alternatively or additionally, the duty cycle of the compressor of the refrigerant circuit can also detected as an operating parameter and the heating device can be controlled in dependence on the detected duty cycle.

The control of the refrigerant flow can be used particularly advantageously by heating the capillary tube and producing vapor in the capillary tube in refrigerator units and/or freezer units with different temperature zones, in particular if different evaporators are provided for the corresponding temperature zones. The unit can, for example, have a freezer compartment evaporator and a refrigerator compartment evaporator which are advantageously connected in succession such that the refrigerant first circulates through the freezer compartment evaporator and then through the refrigerator compartment evaporator.

In particular only one single capillary tube with a heating device associated with it is provided in the named arrangement in which the refrigerant first flows through the freezer compartment evaporator and then through the refrigerator compartment evaporator. By the heating of the capillary tube provided upstream of the freezer compartment evaporator, the refrigerant amount entering into the freezer compartment evaporator can be reduced as required, whereby the refrigerant amount is optionally consumed, so-to-say, completely in the freezer compartment evaporator and the downstream refrigerator section evaporator does not undergo any further cooling. With such a minimal solution, which is extremely cost-favorable in manufacture, the problem regularly occurs in the prior art that either the freezer compartment is not operated coldly enough or the refrigerator section is operated too coldly depending on the ambient temperature. This problem can be eliminated in a simple manner by the heating of the capillary tube disposed in front of the freezer section evaporator.

By a direct bringing about of a deficiency in refrigerant and by corresponding running times, a desired temperature difference can be established between the refrigerator compartment and the freezer compartment. This solution has the advantage with respect to the current winter circuit with a lamp circuit or heating in the interior of the unit that no heating of the interior space is necessary, whereby energetic advantages result and disadvantages for the stored foodstuffs are avoided.

In accordance with a further advantageous embodiment of the invention, the refrigerator circuit can also be configured such that the refrigerant first flows through the refrigerator section evaporator and then through the freezer section evaporator.

In this case, two separate capillary tubes and respective associated heating devices are advantageously provided. In this process, the two capillary tubes are preferably connected in parallel with one another. The refrigerant amount flowing into the refrigerator section evaporator can be controlled in a suitable manner via the one capillary tube, which is connected directly in front of the refrigerator section evaporator, or before the heating of this capillary tube, in order to achieve the desired temperature of the refrigerator section. The refrigerant flowing out of the refrigerator section evaporator is then guided directly into the freezer section evaporator. Since the cold output which can thereby be achieved will, however, not be sufficient for the freezer section evaporator, additional refrigerant can be guided into the freezer section evaporator via the capillary tube connected in parallel. The said capillary tube connected in parallel picks up the refrigerant upstream of the other capillary tube. The refrigerant amount flowing through the freezer section evaporator can be finely adjusted in this process by heating the capillary tube connected in parallel.

The invention will be explained in more detail in the following with respect to a preferred embodiment and to associated drawings. There are shown in the drawings:

FIG. 1: a schematic sectional view of a refrigerator unit and/or freezer unit whose freezer compartment is cooled using a freezer compartment evaporator and whose refrigerator compartment is cooled using a refrigerator compartment evaporator.

FIG. 2: a schematic representation of the refrigerant circuit of the refrigerator unit and/or freezer circuit of FIG. 1; and

FIG. 3: a schematic representation of a refrigerant circuit of the refrigerator unit and/or freezer unit of FIG. 1 in accordance with a further preferred embodiment of the invention.

A refrigerator unit and/or freezer unit 1 is drawn in FIG. 1 whose unit body 2 can be closed by a throughgoing unit door 3. The interior space of the unit body 2 is divided into a freezer compartment 4 and a refrigerator compartment 5, with the freezer compartment 4 being closable by an inner door 6 in the embodiment shown. Storage trays 7 and a drawer-like vegetable pull-out 8 are arranged in a known manner in the refrigerator compartment 5.

The freezer compartment 4 is cooled by a freezer compartment evaporator 9 which can surround the freezer compartment 4 on five sides. The refrigerator compartment 5, in contrast, is cooled by a refrigerator compartment evaporator 10 which extends at the rear wall of the refrigerator compartment 5.

As FIG. 2 shows, the freezer compartment evaporator 9 and the refrigerator compartment evaporator 10 are part of a refrigerant circuit 11 which moreover comprises a compressor 12, a condenser 13 as well as a capillary tube 14 upstream of the two evaporators 9 and 10. In the embodiment shown, the freezer compartment evaporator 9 is arranged upstream of the refrigerator compartment evaporator 10. As FIG. 2 shows, the two evaporators 9 ad 10 are connected sequentially in series so that the refrigerant flowing out of the freezer section evaporator 9 is guided into the refrigerator section evaporator 10. A capillary tube 14 is only provided upstream of the freezer section evaporator 9 arranged upstream.

The capillary tube 14 is provided with a heating device 16 whose heating elements can each heat the end section of the respective capillary tubes 14 and 15 at the downstream side. In accordance with the embodiment shown in accordance with FIG. 2, the heating device 16 can advantageously also be arranged at the end of the capillary tube at the upstream side, whereby a very precise control of the refrigerant passage can be achieved. The heating device 16 can be a simple resistance heating element and can advantageously be temperature regulated in a stepless manner. For this purpose, the heating device 16 is controllable by a temperature control module of an electronic control device 18 which, in another respect, also controls the operation of the compressor 12.

In the embodiment shown, the refrigerant flowing out of the condenser first flows into the capillary tube 14 arranged in front of the freezer compartment evaporator 9. If this capillary tube 14 is not heated, the refrigerant flows in a conventional manner into the freezer compartment evaporator 9. The refrigerant leaving the freezer compartment evaporator 9 then flows to the refrigerator compartment evaporator 10. If, in contrast, the capillary tube 14 connected before the freezer compartment evaporator 9 is heated by the heating device 16 and vapor is produced in the capillary tube 14, the refrigerant passage through the capillary tube 14 optionally reduces toward zero. An undercooling of the refrigerator section can thereby be prevented. If the refrigerant amount is correspondingly reduced by heating the capillary tube 14, the remaining refrigerant amount entering into the freezer section evaporator 9 is evaporated there and consumed, so-to-say, such that a further cooling of the freezer section evaporator 10 is prevented or correspondingly reduced.

As FIG. 2 shows, the control device 18 can be connected to a plurality of temperature sensors 21 and 22 which measure the refrigerator compartment evaporator temperature or the refrigerator compartment temperature and/or the ambient temperature. The control device 18 controls the heating device 16 and the compressor 12 in dependence on the temperatures detected. The control device 18 advantageously only has to take account of one further operating parameter or ambient parameter, in addition to the refrigerator section evaporator temperature or the refrigerator compartment temperature, which is detected by the temperature sensor 21, for the control of the heating device 16 and thus the control of the refrigerant inflow into the freezer section evaporator 9. This can be the ambient temperature which, as shown in FIG. 2, can be detected with an ambient temperature sensor 22. Alternatively or additionally, the freezer section evaporator temperature or the freezer compartment temperature can, however, also be used as the second operating parameter. In this case, the control device 18 would include a corresponding freezer section temperature sensor. Alternatively or additionally, however, it would also be possible to control the heating device 16 in dependence on the relative duty cycle of the compressor 12.

FIG. 3 shows an alternative embodiment of the invention. The refrigerant circuit 11 here likewise includes the refrigerator compartment evaporator 10 and freezer compartment evaporator 9 connected to one another in series, with, however the refrigerator compartment evaporator 10 being arranged upstream of the freezer compartment evaporator 9 in this embodiment. The refrigerant circuit 11 naturally also includes a compressor 12 and a condenser 13 here.

As FIG. 3 shows, two capillary tubes 14 and 15 a well as heating devices 16 and 17 associated with them are used in this embodiment for the control of the refrigerant flow through the two evaporators 9 and 10. The first capillary tube 14 is connected directly in front of the refrigerator compartment evaporator 10. The refrigerant line branches upstream of the said capillary tube 14. At the distributor point 18, a bypass line leading around the refrigerator compartment evaporator 10 branches off and leads to the capillary tube 15 which is connected in parallel and with which the second heating device 17 is associated. As FIG. 3 shows, the capillary tube 15 opens into the freezer compartment evaporator 9.

In this configuration of the refrigerant circuit 11, a precise control of the desired temperature difference of the two evaporators can be achieved: The refrigerant flow which should enter into the refrigerator compartment evaporator 10 can be controlled precisely via the heating of the capillary tube 14 using the heating device 16. The refrigerant flow leaving the refrigerator compartment evaporator 10 then flows through the freezer compartment evaporator 9. If this refrigerant flow is not sufficient for the cooling of the freezer compartment evaporator 9 to the desired temperature, which will be the case as a rule, additional refrigerant is guided into the freezer compartment evaporator 9 via the capillary tube 15 connected in parallel. The refrigerant amount supplied in this process can be controlled precisely by the heating of the capillary tube 15 via the second heating device 17.

The two heating devices 16 and 17 are also controlled by the control device 18 here. The latter is connected to temperature sensors 20 and 21 by means of which the temperatures in the refrigerator compartment and in the freezer compartment or in the refrigerator compartment evaporator and freezer compartment evaporator are detected. 

1. A refrigerator unit and/or a freezer unit comprising a refrigerant circuit (11), which has a compressor (12), a condenser (13), at least one capillary tube (14, 15), at least one evaporator (9, 10), and a control device (16, 17, 18) for the control of the refrigerant flow through the refrigerant circuit (11), wherein the control device has a heating device (16, 17) for the heating of the at least one capillary tube (14, 15) and has a vapor production in the capillary tube (14, 15) by which the refrigerant flow through the refrigerant circuit (11) can be controlled.
 2. A refrigerator unit and/or a freezer unit in accordance with claim 1, wherein the control device (18) and/or the refrigerant circuit (11) is made free of flow regulator valves and on/off valves.
 3. A refrigerator unit and/or a freezer unit in accordance with claim 1, wherein the refrigerant circuit (11) has flow regulator and/or on/off valves, in addition to the heatable capillary tubes for the control of the refrigerant flow.
 4. A refrigerator unit and/or a freezer unit in accordance with claim 1, wherein the heating device (16, 17) is arranged at an end section of the capillary tube (14, 15) at the downstream side.
 5. A refrigerator unit and/or a freezer unit in accordance with claim 1, wherein the heating device (16, 17) is arranged an inlet section of the capillary tube (14, 15) at the upstream side.
 6. A refrigerator unit and/or a freezer unit in accordance with claim 1, wherein the heating device (16, 17) is preferably made with a stepless temperature control and the control device (18) has a temperature control module for the control of the heating device (16, 17).
 7. A refrigerator unit and/or a freezer unit in accordance with claim 1, wherein at least one temperature sensor (20, 21, 22) is provided for the detection of an evaporator temperature, of a freezer compartment temperature, of a refrigerator compartment temperature and/or an ambient temperature and the control device (18) controls the heating device (16 17) in dependence on the temperature detected.
 8. A refrigerator unit and/or a freezer unit in accordance with claim 1, wherein the operating time detection device is provided for the detection of the operating time of the compressor (12) and the control device (18) controls the heating device (16, 17) in dependence on the detected operating times of the compressor (12).
 9. A refrigerator unit and/or a freezer unit in accordance with claim 1, wherein a plurality of evaporators (9, 10) are provided, in particular a refrigerator compartment evaporator (10) and a freezer compartment evaporator (9) which are connected sequentially in series.
 10. A refrigerator unit and/or a freezer unit in accordance with claim 9, wherein the freezer compartment evaporator (9) is arranged upstream of the refrigerator compartment evaporator (10) in the refrigerant circuit (11).
 11. A refrigerator unit and/or a freezer unit in accordance with claim 10, wherein only one capillary tube (14) is associated with the freezer compartment evaporator (9) and the refrigerator compartment evaporator (10) and is arranged upstream of the freezer compartment evaporator (9) and is heatable by a heating device (16).
 12. A refrigerator unit and/or a freezer unit in accordance with claim 11, wherein the control device controls the heating device (16) of the only one capillary tube (14) in dependence on the signal of a refrigerator compartment temperature sensor or of a refrigerator compartment evaporator temperature sensor (21) and on only one further detected operating parameter, with the additional operating parameter being selected from the following group: freezer compartment temperature or freezer compartment evaporator temperature, ambient temperature and relative duty cycle of the compressor (12).
 13. A refrigerator unit and/or a freezer unit in accordance with claim 9, wherein the freezer compartment evaporator (9) is arranged downstream of the refrigerator compartment evaporator (10) in the refrigerant circuit (11).
 14. A refrigerator unit and/or a freezer unit in accordance with claim 13, wherein two capillary tubes (14, 15) are associated with the two evaporators (9, 10), are connected to one another in parallel and are both connected to a branching point (18) at the inflow side which is arranged upstream of the refrigerator compartment evaporator (10) and downstream of the condenser (13), with the one capillary tube (14) opening directly into the refrigerator compartment evaporator (10) and the other capillary tube (15) opening directly into the freezer compartment evaporator (9).
 15. A refrigerator unit and/or a freezer unit in accordance with claim 14, wherein a respective heating device (16, 17) is associated with the two capillary tubes (14, 15), with the control device (18) controlling the two heating devices (16, 17) in dependence on the signals of a temperature sensor (21) for a refrigerator compartment or for a refrigerator compartment evaporator and of a temperature sensor (20) for a freezer compartment or for a freezer compartment evaporator.
 16. A refrigerator unit and/or a freezer unit (1) comprising a refrigerator circuit (11) having a compressor (12), a condenser (13), a capillary tube (14, 15) and an evaporator (9, 10), wherein at least one operating parameter and/or ambient parameter of the refrigerator unit and/or freezer unit (1) is detected, the refrigerant flow through the refrigerant circuit (11) is controlled in dependence on the detected operating parameter and/or ambient parameter, the refrigerant flow through the refrigerant circuit (11) is controlled by the capillary tube (14, 15) being heated by a heating device (16, 17) and refrigerant flowing through the capillary tube (14, 15) being brought to evaporation in the capillary tube (14, 15).
 17. A refrigerator unit and/or a freezer unit in accordance with claim 16, wherein an evaporator temperature, a freezer compartment temperature, a refrigerator compartment temperature and/or an ambient temperature is detected as the operating parameter of the refrigerator unit and/or freezer unit (1) and the heating output and/or the heating time of the heating device (16,17) is controlled in dependence on the detected evaporator temperature, refrigerator compartment temperature, freezer compartment temperature and/or ambient temperature.
 18. A method in accordance with claim 16, wherein a duty cycle of the compressor (12) is detected as the operating temperature of the refrigerator unit and/or freezer unit (1) and the heating output and/or the heating time of the heating device (16, 17) is controlled in dependence on the detected duty cycle of the compressor (12).
 19. A method in accordance with claim 17, wherein a duty cycle of the compressor (12) is detected as the operating temperature of the refrigerator unit and/or freezer unit (1) and the heating output and/or the heating time of the heating device (16, 17) is controlled in dependence on the detected duty cycle of the compressor (12).
 20. A refrigerator unit and/or a freezer unit in accordance with claim 2, wherein the heating device (16, 17) is arranged at an end section of the capillary tube (14, 15) at the downstream side. 